Validation of the 5-min irradiance from the National Solar Radiation Database (NSRDB)

The National Solar Radiation Database (NSRDB) offers satellite-derived irradiance over most of the Americas. The latest version of the NSRDB hosts broadband irradiance estimates at 5-min–2-km resolution, which have improved from the previous 30-min–4-km resolution. Whereas this new dataset is expected to continue providing invaluable solar resource information to researchers and practitioners worldwide, its accuracy needs to be validated. Validating high-resolution data must go beyond reporting the overall error metrics. To that end, time series features are used here to study the correspondence between the satellite-derived and measured irradiance transients. This paper also provides an in-depth discussion on the data quality issues observed during the validation.